U.S. patent number 10,578,274 [Application Number 15/444,608] was granted by the patent office on 2020-03-03 for lens array assembly and method for making the same.
This patent grant is currently assigned to General Electric Company. The grantee listed for this patent is General Electric Company. Invention is credited to Mark Marshall Meyers, Loucas Tsakalakos.
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United States Patent |
10,578,274 |
Meyers , et al. |
March 3, 2020 |
Lens array assembly and method for making the same
Abstract
A lens array assembly includes plural lens elements each
configured to receive incoming light from one or more light
sources. The lens elements include biconic refractive elements on
first sides of the lens elements and including diffractive elements
on opposite, second sides of the lens elements. The lens elements
are configured to change directions of the incoming light received
from the one or more light sources such that outgoing light
emanating from the lens elements is collimated in a first direction
but diverges along a different, second direction.
Inventors: |
Meyers; Mark Marshall
(Niskayuna, NY), Tsakalakos; Loucas (Niskayuna, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
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Assignee: |
General Electric Company
(Schenectady, NY)
|
Family
ID: |
60572482 |
Appl.
No.: |
15/444,608 |
Filed: |
February 28, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170356621 A1 |
Dec 14, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62348291 |
Jun 10, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F21V
5/007 (20130101); H01S 5/02415 (20130101); F21V
5/08 (20130101); G02B 19/0057 (20130101); G08G
5/0047 (20130101); H01S 5/0071 (20130101); G02B
27/425 (20130101); F21V 13/04 (20130101); F21K
9/90 (20130101); F21V 14/04 (20130101); G02B
3/0012 (20130101); G02B 19/0009 (20130101); H01S
5/0683 (20130101); F21K 9/68 (20160801); G02B
3/005 (20130101); F21K 9/69 (20160801); F21Y
2115/30 (20160801); H01S 5/005 (20130101); F21W
2111/06 (20130101); H01S 5/4025 (20130101) |
Current International
Class: |
F21V
5/00 (20180101); H01S 5/0683 (20060101); G02B
19/00 (20060101); H01S 5/00 (20060101); F21V
5/08 (20060101); G02B 27/42 (20060101); G02B
3/00 (20060101); H01S 5/024 (20060101); F21K
9/68 (20160101); F21K 9/69 (20160101); F21K
9/90 (20160101); F21V 13/04 (20060101); F21V
14/04 (20060101); G08G 5/00 (20060101) |
Field of
Search: |
;362/326,608,615,520,217.02,244 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Dillon et al., "Microlens fabrication using HEBS glass for compact
high-resolution IR imaging system", 2006, 9 pages, Proc. of SPIE
vol. 6327 63270B-8, Nanoengineering: Fabrication, Properties,
Optics, and Devices III. cited by applicant .
Lu et al., "Direct write of microlens array using digital
projection photopolymerization" Online publication, Applied
Physicas Letteres 92, Jan. 30, 2008, 3 pages, American Institute of
Physics. cited by applicant .
Tien et al., "Microcontact Printing of SAMs", 1998, 24 pages, vol.
24, Thin Films by Academic Press, Department of Chemistry and
Chemical Biology, Harvard University, Cambridge, Massachusetts.
cited by applicant .
Koshelev et al., "High refractive index Fresnel lens on a fiber
fabricated by nanoimprint lithography for immersion applications" 4
pages, Opt. Lett. 41, (2016). cited by applicant .
Wang et al., "Diffractive Optics: Nanoimprint lithography enables
fabrication of subwavelength optics" Dec. 1, 2005, 6 pages, Laser
Focus World, Somerset, NJ. cited by applicant .
Wavelength Electronics "Laser Diode Driver Basics"
TeamWavelength.com (4 pages). cited by applicant.
|
Primary Examiner: Carter; William J
Assistant Examiner: Cadima; Omar Rojas
Attorney, Agent or Firm: Carroll; Christopher R. The Small
Patent Law Group LLC
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application
No. 62/348,291, which was filed on 10 Jun. 2016, and the entire
disclosure of which is incorporated herein by reference.
Claims
What is claimed is:
1. A lens array assembly comprising: a single body lens array that
forms plural lens elements each configured to receive incoming
light from one or more light sources, the lens elements including
biconic refractive elements on a first side of the single body lens
array and including diffractive elements on an opposite, second
side of the single body lens array, wherein the lens elements are
configured to change directions of the incoming light received via
the first side of the single body lens array from the one or more
light sources such that outgoing light emanating from the second
side of the single body lens array is collimated in a first
direction but diverges along a different, second direction.
2. The lens array assembly of claim 1, wherein the lens elements
are configured to receive the incoming light from the one or more
light sources through the diffractive elements and the outgoing
light emanates out of the lens elements from the biconic refractive
elements.
3. The lens array assembly of claim 1, wherein each of the lens
elements is configured to form a different diverging beam of the
outgoing light.
4. The lens array assembly of claim 3, wherein each of the lens
elements is configured to form the diverging beam of the outgoing
light such that the diverging beam emanating from each of the lens
elements only partially overlaps the diverging beam emanating from
at least one neighboring lens element of the lens elements.
5. The lens array assembly of claim 3, wherein each of the lens
elements is configured to form the diverging beam of the outgoing
light such that the diverging beam emanating from each of the lens
elements has a different central angle than the diverging beam
emanating from other lens elements in the lens elements.
6. The lens array assembly of claim 1, wherein the lens elements
are configured to receive the incoming light from laser diodes as
the light sources.
7. The lens array assembly of claim 1, wherein each of the lens
elements is configured to receive a portion of the incoming light
from a different light source of the one or more light sources.
8. The lens array assembly of claim 1, wherein the lens elements
are static and do not move, but that change the directions of the
incoming light received from the plural light sources such that the
outgoing light emanating from the lens elements is collimated in
the first direction but diverges along the second direction.
9. The lens array assembly of claim 1, wherein the lens elements
are disposed side-by-side along the second direction.
10. A lens array assembly comprising: a single body lens array
forming plural lens elements each configured to receive incoming
light from one or more light sources, the lens elements including
biconic refractive elements on first sides of the lens elements and
including diffractive elements on opposite, second sides of the
lens elements, wherein the lens elements are configured to form
different diverging beams of the outgoing light such that the
diverging beams emanating from the lens elements have different
central angles.
11. The lens array assembly of claim 10, wherein the lens elements
are configured to form the diverging beams of the outgoing light
such that the diverging beam emanating from each of the lens
elements only partially overlaps the diverging beam emanating from
at least one neighboring lens element of the lens elements.
12. A lens assembly comprising: a lens array formed from a single
body in a shape of plural micro lenses, each of the micro lenses
having a biconic refractive element on a first side of the lens
array and a diffractive element on an opposite, second side of the
lens array, wherein the micro lenses are configured to change
directions of incoming light received via the first side of the
lens array from light sources such that outgoing light emanating
from the second side of the lens array is collimated in a first
direction but diverges along a different, second direction.
13. The lens assembly of claim 12, wherein the micro lenses are
configured to receive the incoming light from the light sources
through the diffractive elements and the outgoing light emanates
out of the micro lenses from the biconic refractive elements.
14. The lens assembly of claim 12, wherein each of the micro lenses
is configured to form a differently shaped diverging beam of the
outgoing light such that the diverging beam from each of the micro
lenses does not completely overlap the diverging beam from any
other of the micro lenses.
15. The lens assembly of claim 14, wherein each of the micro lenses
is configured to form the diverging beam of the outgoing light such
that the diverging beam emanating from each of the micro lenses has
a different central angle than the diverging beam emanating from
all other micro lenses.
16. The lens assembly of claim 12, wherein the micro lenses are
configured to receive the incoming light from laser diodes.
17. The lens assembly of claim 12, wherein each of the micro lenses
is configured to receive a portion of the incoming light from a
different light source.
18. The lens assembly of claim 12, wherein the micro lenses are
static and do not move, but that change the directions of the
incoming light such that the outgoing light emanating from the lens
elements is collimated in the first direction but diverges along
the second direction.
19. The lens assembly of claim 12, wherein the micro lenses are
disposed side-by-side along the second direction.
Description
FIELD
The subject matter described herein relates to lens arrays, such as
microlens arrays.
BACKGROUND
Various lighting assemblies use lenses in order to shape and direct
light in a variety of directions and shapes. Some lighting
assemblies can be used as beacons to direct aircraft into a landing
area or zone. These types of lighting assemblies frequently have
large and heavy light sources which require correspondingly large
and heavy lenses to direct the light toward aircraft to operate as
the beacon for the aircraft. Other lighting assemblies can use
lenses to direct light for a variety of purposes, such as
illumination, distance measurement (e.g., LIDAR), or the like.
Improvements in some lighting assemblies may seek to reduce the
size and weight of the light sources, but a need still exists for
lenses that are able to shape and direct light from the light
sources. The lighting assemblies and lenses decrease in size, the
ability to manufacture sufficiently small lenses that also can
shape and direct the light across a large area to operate as an
aircraft beacon, to illuminate an area, to measure distances, etc.,
becomes increasingly difficult.
BRIEF DESCRIPTION
In one embodiment, a lens array assembly is provided that includes
plural lens elements each configured to receive incoming light from
one or more light sources. The lens elements include biconic
refractive elements on first sides of the lens elements and
including diffractive elements on opposite, second sides of the
lens elements. The lens elements are configured to change
directions of the incoming light received from the one or more
light sources such that outgoing light emanating from the lens
elements is collimated in a first direction but diverges along a
different, second direction.
In one embodiment, a method (e.g., for providing a lens array
assembly) includes obtaining a grayscale photomask, applying a
photoresist to a first side of an optic body, forming one or more
insoluble portions in the photoresist by exposing the photoresist
to a developing light through the grayscale photomask, and exposing
the one or more insoluble portions in the photoresist and one or
more portions of the optic body on the first side that are outside
of the one or more insoluble portions of the photoresist to an
etchant. The etchant forms biconic refractive surfaces in plural
lens elements on the first side of the optic body. The lens
elements are configured to change directions of incoming light
received from one or more light sources such that outgoing light
emanating from the lens elements is collimated in a first direction
but diverges along a different, second direction.
In one embodiment, a lens array assembly includes plural lens
elements each configured to receive incoming light from one or more
light sources. The lens elements include biconic refractive
elements on first sides of the lens elements and including
diffractive elements on opposite, second sides of the lens
elements. The lens elements are configured to form different
diverging beams of the outgoing light such that the diverging beams
emanating from the lens elements have different central angles.
BRIEF DESCRIPTION OF THE DRAWINGS
The present inventive subject matter will be better understood from
reading the following description of non-limiting embodiments, with
reference to the attached drawings, wherein below:
FIG. 1 illustrates a lighting assembly that is included in a
lighting system and that includes one embodiment of a lens array
assembly;
FIG. 3 illustrates a perspective view of one embodiment of a lens
array assembly;
FIG. 3 illustrates a perspective view of another embodiment of a
lens array assembly;
FIG. 4 illustrates one example of the light emanating from the lens
elements shown in FIG. 1 of the lens array assemblies along a
vertical direction;
FIG. 5A illustrates an example of light emanating from a lens
element along a horizontal direction;
FIG. 5B illustrates an example of light emanating from another lens
element along the horizontal direction;
FIG. 5C illustrates an example of light emanating from another lens
element along the horizontal direction;
FIG. 5D illustrates an example of light emanating from another lens
element along the horizontal direction;
FIG. 5E illustrates an example of light emanating from another lens
element along the horizontal direction;
FIG. 5F illustrates an example of light emanating from another lens
element along the horizontal direction;
FIG. 6 illustrates outgoing light emanating from a group of the
lens elements according to one embodiment;
FIG. 7 illustrates the lens array assembly shown in FIGS. 2 and 3
at one stage of manufacture according to one embodiment;
FIG. 8 illustrates the lens array assembly shown in FIGS. 2 and 3
at another stage of manufacture according to one embodiment;
FIG. 9 illustrates the lens array assembly shown in FIGS. 2 and 3
at another stage of manufacture according to one embodiment;
FIG. 10 illustrates the lens array assembly shown in FIGS. 2 and 3
at another stage of manufacture according to one embodiment;
FIG. 11 illustrates the lens array assembly shown in FIGS. 2 and 3
at another stage of manufacture according to one embodiment;
FIG. 12 illustrates the lens array assembly shown in FIGS. 2 and 3
at another stage of manufacture according to one embodiment;
FIG. 13 illustrates a flowchart of one embodiment of a method for
providing the lens array assemblies shown in FIGS. 2 and 3;
FIG. 14 illustrates a front surface of one lens element according
to one example;
FIG. 15 illustrates a rear surface of the lens element shown in
FIG. 14 according to one example;
FIG. 16 illustrates a front surface of another lens element
according to one example;
FIG. 17 illustrates a rear surface of the lens element shown in
FIG. 16 according to one example;
FIG. 18 illustrates a front surface of another lens element
according to one example;
FIG. 19 illustrates a rear surface of the lens element shown in
FIG. 18 according to one example;
FIG. 20 illustrates a front surface of another lens element
according to one example;
FIG. 21 illustrates a rear surface of the lens element shown in
FIG. 20 according to one example;
FIG. 22 illustrates a front surface of another lens element
according to one example;
FIG. 23 illustrates a rear surface of the lens element shown in
FIG. 22 according to one example;
FIG. 24 illustrates a front surface of another lens element
according to one example; and
FIG. 25 illustrates a rear surface of the lens element shown in
FIG. 24 according to one example.
DETAILED DESCRIPTION
The inventive subject matter described herein provides lens array
assemblies and methods for manufacturing the lens array assemblies.
In one embodiment, the lens array assemblies include a segmented
micro optic lens array that redirects and controls the divergence
of light (e.g., laser light) in a first direction (e.g., the
horizontal direction), while collimating the light in a different,
second direction (e.g., the vertical direction). The lens array
assembly utilizes an array of N light sources (e.g., laser diodes),
where the beams of light generated by the light sources is
collimated in the second direction (e.g., the vertical direction)
and diverges as 1/Nth of the full angular range in the first
direction (e.g., the horizontal direction). The micro lens array
assembly is configured to have progressively larger horizontal
element decentration on lens elements (also referred to as
lenslets) as one moves radially away from the center of the array.
This causes the axial ray from light sources progressively farther
from the center to be deflected at larger angles. By deflecting the
beams towards the center, the required size of a scanning mirror
that reflects the light is greatly reduced, which makes the
assembly compatible with the integrated photonic manufacturing
approach on much smaller scales (e.g., sizes) than is currently
available.
FIG. 2 illustrates a lighting assembly 200 that is included in a
lighting system and that includes one embodiment of a lens array
assembly 202. One or more lighting assemblies 200 can be used in a
lighting system to generate light for operating as a beacon for
aircraft. The lighting system uses the lens array assemblies to
direct light into a pyramid or other shape. The aircraft can then
use the light to determine where to land on a surface.
Alternatively, the lighting system includes the lighting assembly
or assemblies for one or more other purposes.
The lighting assembly 200 includes several light sources 204 that
generate light toward the lens array assembly 202. These light
sources 204 can be photodiodes and/or laser diodes that generate
different beams of light into different areas of the lens array
assembly 202. For example, the lens array assembly 202 can include
multiple micro lenses 206 that each receives light from a different
light source 204. In the illustrated embodiment, the lens array
assembly 202 includes nine lens elements, or lenses, 206.
Alternatively, the lens array assembly 202 can include a single
lens element 206 or a different number of lens elements 206. For
example, the lens array assembly 202 can have twelve lens elements
206.
The light sources 204 can all generate light having the same or
substantially the same (e.g., within 3%) wavelength, such as 1570
nanometers. This light is received by the lens elements 206 into or
through a back surface or side 210 of each lens element 206. The
light that is generated by the light sources 204 and received by
the lens elements 206 can be referred to as incoming light. The
light passes through the lens elements 206, is collimated,
diffracted, and/or refracted by the lens elements 206, and exits or
emanates from opposite front surfaces or sides 212 of the lens
elements 206 as outgoing light. Current driving circuitry 208 can
control the light output by each light source 204. Optionally,
another type of light source 204 can be used, or at least one of
the light sources 204 can generate light that is received by two or
more of the lens elements 206.
As described below, the lens elements 206 include biconic
refractive surfaces (also referred to as biconic refractive
elements) on the front sides 212 of the lens elements 206 and
diffractive surfaces (also referred to as diffractive elements) on
the opposite, back sides 212 of the lens elements 206. The lens
elements 206 are configured to change directions of the incoming
light received from the light sources 204 such that the outgoing
light emanating from the front surfaces or sides 212 of the lens
elements 206 is collimated in a first direction but diverges along
a different, second direction. For example, this outgoing light may
be collimated along or in a vertical direction 214 but diverge or
spread out in an orthogonal direction, such as a horizontal
direction 216 in which the lens elements 206 are arranged
side-by-side.
FIG. 2 illustrates a perspective view of one embodiment of a lens
array assembly 302. The lens array assembly 302 may be used in
place of the lens array assembly 202 in the lighting assembly 200
shown in FIG. 1. One difference between the lens array assemblies
202, 302 is that the lens array assembly 302 includes twelve lens
elements 206 (e.g., lens elements 206A-F), while the lens array
assembly 202 includes nine lens elements 206. Similar to the lens
array assembly 202, the lens elements 206 in the lens array
assembly 302 are arranged side-by-side along the horizontal
direction 216.
The lens elements 206 can be arranged in different groups. For
example, one group of lens elements 206 can include one of each of
the lens elements 206A-F and another group of the lens elements 206
can include another one of each of the lens elements 206A-F. As a
result, the lens elements 206 in the lens array assembly 302 are
arranged in groups that are symmetrical about a center line 300 of
the lens array assembly 302.
FIG. 3 illustrates a perspective view of another embodiment of a
lens array assembly 402. The lens array assembly 402 may be used in
place of the lens array assembly 202 in the lighting assembly 200
shown in FIG. 1. One difference between the lens array assemblies
202, 302 shown in FIGS. 1 and 2 and the lens array assembly 402 is
that the lens array assembly 402 includes a border or frame 400
extending around or encircling the lens elements 206 in the lens
array assembly 402.
Similar to the lens array assembly 302, the lens elements 206 can
be arranged in different groups in the lens array assembly 402. For
example, one group of lens elements 206 can include one of each of
the lens elements 206A-F and another group of the lens elements 206
can include another one of each of the lens elements 206A-F. As a
result, the lens elements 206 in the lens array assembly 402 are
arranged in groups that are symmetrical about a center line 300 of
the lens array assembly 402.
The lens array assemblies 202, 302, 402 may be formed from silicon
or another material. As described below, the lens array assemblies
202, 302, 402 can be formed by applying a photoresist to a silicon
body, exposing the photoresist to light (e.g., ultraviolet light)
through a grayscale mask to form insoluble portions of the
photoresist, and exposing the insoluble portions of the photoresist
and portions of the silicon body outside of the insoluble portions
of the photoresist. Each lens element 206 can be relatively small.
For example, each lens element 206 can have a width dimension
measured along the horizontal direction 216 that is no more than
2.2 millimeters and a height dimension measured along the vertical
direction 214 that is no more than 3.4 millimeters. Optionally, the
lens elements 206 may have a larger width dimension and/or height
dimension.
The lens elements 206 in the lens array assemblies 202, 302, 402
change the shape of the light received from the light sources 204
(shown in FIG. 1) such that the light exiting the lens elements 206
has a different shape. In one embodiment, the shape of the light is
changed by the rear and front surfaces 210, 212 of different lens
elements 206 in different ways. For example, the lens elements 206A
can change the shape of the light in a first direction or shape,
the lens elements 206B can change the shape of the light in a
different, second direction or shape, and so on. The lens elements
206A can change the shape or direction of the light in the same
direction or shape, the lens elements 206B can change the shape or
direction of the light in the same direction or shape, and so
on.
FIG. 4 illustrates one example of the light emanating from the lens
elements 206 (shown in FIG. 1) of the lens array assemblies 202,
302, 402 along the vertical direction 214. A lens array assembly
502 in FIG. 4 represents the lens array assembly 202, the lens
array assembly 302, or the lens array assembly 402. The lens
elements 206 in the lens array assembly 502 receive incoming light
500 from the light sources 204 (shown in FIG. 1). The back surfaces
210 of the lens elements 206 diffract the incoming light 500 for
achromatization and aberration correction in the incoming light
500. The front surfaces 212 of the lens elements 206 refract the
light passing through the lens elements 206 to collimate the light
along the vertical direction 214. For example, the incoming light
500 is diffracted and refracted by each lens element 206 to form a
vertically collimated light beam as outgoing light 504 that
emanates from the front surfaces 212 of the lens elements 206, as
shown in FIG. 4. The outgoing light 504 is collimated in that all
or substantially all (e.g., at least 95%, at least 97%, or at least
99%) of the outgoing light 504 is directed in a parallel,
non-spreading or non-diverging direction when viewed along the
vertical direction 214. In one embodiment, the outgoing light 504
is vertically collimated such that the light is contained within
(and does not substantially extend outside of) a dimension of no
more than 3.4 millimeters.
Conversely, the lens elements 206 can diffract the incoming light
500 so that the outgoing light 504 diverges or spreads out in the
horizontal direction 216. Different lens elements 206 can diverge
the portion of the incoming light 500 received by each lens element
206 differently so that the beams of the outgoing light 504 from
each lens element 206A-F is oriented in a different direction.
FIGS. 5A-F illustrate examples of the light emanating from the lens
elements 206 (shown in FIG. 1) of the lens array assemblies 202,
302, 402 along the horizontal direction 216. Each of FIGS. 5A
through 5F illustrates the portion of the outgoing light 504
emanating from a different one of the lens elements 206A through
206F. The rear surfaces 210 of the lens elements 206 include or are
diffractive surfaces with linear grating, optical power, and
aspheric terms. The grating can reduce the depth to which a body
that is etched to form the lens elements 206 relative to lens
elements that do not include such a grating.
As shown in FIGS. 5A-F, each lens element 206A-F diffracts the
outgoing light 504 so that the beam or portion of the outgoing
light 504 coming from each lens element 206A-F is oriented along a
different central angle 600A-F relative to the front surfaces 212
of the lens elements 206A-F. For example, the lens element 206A can
diffract the incoming light 500 so that a diverging beam 602A of
the outgoing light 504 is oriented (e.g., centered) along a center
direction 604A at a first central angle 600A, the lens element 206B
can diffract the incoming light 500 so that a diverging beam 602B
of the outgoing light 504 is oriented along a different center
direction 604B at a larger second central angle 600B, the lens
element 206C can diffract the incoming light 500 so that a
diverging beam 602C of the outgoing light 504 is oriented along a
different center direction 604C at a larger third central angle
600C, and so on. The central angle 600F of the lens element 206F is
27.5 degrees, the central angle 600E of the lens element 206E is
22.5 degrees, the central angle 600D of the lens element 206D is
17.5 degrees, the central angle 600C of the lens element 206C is
12.5 degrees, the central angle 600B of the lens element 206B is
7.5 degrees, and the central angle 600A of the lens element 206A is
2.5 degrees in one embodiment. Alternatively, one or more different
central angles 600 can be used.
As shown in FIGS. 5A-F, the portion of the outgoing light 504
emanating from each lens element 206A-F can continue to diverge or
spread away from the corresponding center direction 604 at
distances that are farther from the lens element 206. While the
outgoing light 504 coming out from each lens element 206A-F can be
collimated along the vertical direction 214 such that the outgoing
light 504 does not diverge or spread out along the vertical
direction 214 after leaving the front surfaces 212 of the lens
elements 206A-F, the outgoing light 504 can spread out, or diverge,
along the horizontal direction 506. In one embodiment, the outgoing
light 504 diverges along a sixty-degree angle as the outgoing light
504 emanates from the front surfaces 212 of the lens elements
206A-F. Alternatively, the outgoing light 504 diverges along or
within a smaller or larger angle.
FIG. 6 illustrates the outgoing light 504 emanating from a group of
the lens elements 206A-F according to one embodiment. The outgoing
light 504 illustrates the combined distribution or spread of the
light emanating from the group of lens elements 206A-F along the
horizontal direction 216. The location of the lens elements 206 and
the orientation of the different center directions 604 of the
outgoing light 504 from each lens element 206 can result in the
portion of the outgoing light 504 from one or more lens elements
206 overlapping or crossing the portion of the outgoing light 504
from one or more other lens elements 206 before the focal point of
the light, as shown in FIG. 6. The combination of the vertically
collimated outgoing light 504 (shown in FIG. 4) and the
horizontally diverging or spread outgoing light 504 (shown in FIG.
4) can create a linear shape of light, such as one of several lines
of light generated by the lighting system described above. As shown
in FIG. 6, the portion of the outgoing light 504 emanating from
each lens elements 206A-F only partially overlaps (e.g., by three
degrees or less) the portion of the outgoing light 504 emanating
from the neighboring lens element 206 or each of the portions of
the outgoing lights 504 emanating from the neighboring lens
elements 206 on each side of the lens element 206. This overlap
occurs after the portions of outgoing light 504 have crossed over
each other.
As shown in FIGS. 2 and 3, multiple sets or groups of the lens
elements 206A-F are included in the lens array assembly 402 in one
embodiment. Each group or set of the lens elements 206A-F can
create a different portion of the horizontally spread out outgoing
light 504 shown in FIG. 6. For example, another group or set of the
lens elements 206A-F can create another outgoing light 504 shown in
FIG. 6, but that is on one side of the outgoing light 504 shown in
FIG. 6.
FIGS. 7 through 12 illustrate the lens array assembly 302, 402
shown in FIGS. 2 and 3 at various stages of manufacture according
to one embodiment. With continued reference to FIGS. 7 through 12,
FIG. 13 illustrates a flowchart of one embodiment of a method 1400
for providing the lens array assembly 302, 402. At 1402, a glass
body 800 (shown in FIG. 7) is exposed to electron beams 802 (shown
in FIG. 7) to form a grayscale photomask 900 (shown in FIG. 8). The
glass body 800 can be a planar sheet of high energy beam selective
(HEBS) glass. The photomask 900 can have portions 902 that are more
transparent to a photoresist curing light, such as ultraviolet
light, and other portions 904 that are less transparent to the
curing light. The locations in the photomask 900 that are more
transparent to the curing light can represent the areas of the
glass body 800 that is to be etched or removed from the glass body
800 to form the lens elements 206 (shown in FIG. 1) less than the
locations in the photomask 900 that are less transparent to the
curing light.
At 1404, a photoresist 1000 is applied to an optic body 1002. The
photoresist 1000 can be applied in an even or substantially even
thickness (e.g., within manufacturing tolerances of the components
used to apply the photoresist 1000). The optic body 1002 may be a
sheet or planar body of a material that receives, diffracts, and
refracts light as described herein. In one embodiment, the optic
body 1002 is a sheet of silicon. Alternatively, the optic body 1002
is formed from another material, such as a glass or polymer. The
optic body 1002 is relatively thin prior to etching (described
below). For example, the optic body 1002 can be formed from a sheet
of silicon that is no thicker than one millimeter. Alternatively, a
thicker or thinner optic body 1002 can be used.
At 1406, the photoresist 1000 is developed. Developing the
photoresist 1000 can include positioning the photomask 900 between
the photoresist 1000 and a source of curing light 1004, such as an
ultraviolet light source. The curing light 1004 passes through the
photomask 900 and is attenuated different amounts by the photomask
900 depending on how much of the photomask 900 was removed in
various areas at 1402. For example, portions 1006 of the
photoresist 1000 that are between the areas of the photomask 900
that attenuate little to none of the curing light are cured and
become insoluble portions 1006 of photoresist 1000. Portions 1008
of the photoresist 1000 that are between the areas of the photomask
900 that attenuate a significant portion or all of the curing light
are not cured. These portions 1008 of the photoresist 1000 remain
soluble.
The soluble portions 1008 of the photoresist 1000 can be removed by
exposing the insoluble portions 1006 and soluble portions 1008 of
the photoresist 1000 to a solvent. The solvent can remove the
soluble portions 1008 of the photoresist 1000 so that only the
insoluble portions 1006 remain.
At 1408, the insoluble portions 1006 of the photoresist 1000 and
the optic body 1002 are exposed to an etchant 1200, as shown in
FIG. 11. In one embodiment, the etchant 1200 is a plasma etch, but
optionally can be a chemical or other type of etchant. The etchant
1200 can remove portions of the optic body 1002 that are beneath or
that were beneath the soluble portions 1008 of the photoresist
1000. The etchant 1200 also can remove portions of the insoluble
portions 1006 of the photoresist 1000. The etchant 1200 removes
portions of the optic body 1002 to form the lens elements 206
described above, as shown in FIG. 13. Optionally, a laser etch can
be used to form the lens elements 206 instead of or in addition to
the photoresist etch technique described above.
The process described above can be repeated for the other surface
of the optic body 1002. For example, the method 1400 can be
performed once for one side of the optic body 1002 to form the
front surfaces 212 of the lens elements 206 using a first photomask
900, and the method 1400 can be repeated for the other, opposite
side of the optic body 1002 to form the rear surfaces 210 of the
lens elements 206 using a different, second photomask 900.
The amount of material of the optic body 1002 that is removed to
form the front and rear surfaces 212, 210 of the lens elements 206
is relatively small. For example, no more than 62.5 microns is
removed from the optic body 1002 to form the lens elements 206 in
one embodiment. Alternatively, a larger or smaller amount of the
optic body 1002 can be removed. For example, no more than 32
microns can be removed from one side of the optic body 1002 to form
the front surfaces 212 of the lens elements 206 and no more than
3.2 microns can be removed from the opposite side of the optic body
1002 to form the rear surfaces 210 of the lens elements 206 in
another embodiment.
FIGS. 14 through 25 illustrate front and rear surfaces 212, 210 of
the lens elements 206 according to one example. FIG. 14 illustrates
the front surface 212 of the lens element 206F and FIG. 15
illustrates the back surface 210 of the lens element 206F. FIG. 16
illustrates the front surface 212 of the lens element 206E and FIG.
17 illustrates the back surface 210 of the lens element 206E. FIG.
18 illustrates the front surface 212 of the lens element 206D and
FIG. 19 illustrates the back surface 210 of the lens element 206D.
FIG. 20 illustrates the front surface 212 of the lens element 206C
and FIG. 21 illustrates the back surface 210 of the lens element
206C. FIG. 22 illustrates the front surface 212 of the lens element
206B and FIG. 23 illustrates the back surface 210 of the lens
element 206B. FIG. 24 illustrates the front surface 212 of the lens
element 206A and FIG. 25 illustrates the back surface 210 of the
lens element 206A.
The front surfaces 212 and the rear surfaces 210 of the lens
elements 206A-F are shown alongside a first axis 1500
representative of horizontal distances along the horizontal
direction 216 from a vertical center line of the lens element 206,
a perpendicular second axis 1502 representative of vertical
distances along the vertical direction 214 from a horizontal center
line of the lens element 206, and a perpendicular third axis 1504
representative of thickness of the lens element 206 from the center
of the lens element 206. The units of the axes 1500, 1502, 1504 are
millimeters.
The front surfaces 212 of the lens elements 206A-F are biconic
surfaces that refract the portion of the outgoing light emanating
from the lens elements 206. These surfaces are curved along two
different directions with different radii of curvature in each
direction in one embodiment. The front and rear surfaces 212, 210
of the lens elements 206 are formed as Fresnel lenses or lenslets
to reduce the needed thickness of the lens elements 206. In one
embodiment, each of the front and rear surfaces 212, 210 are a
fifth order diffractive Fresnel lens.
In one embodiment, a lens array assembly is provided that includes
plural lens elements each configured to receive incoming light from
one or more light sources. The lens elements include biconic
refractive elements on first sides of the lens elements and
including diffractive elements on opposite, second sides of the
lens elements. The lens elements are configured to change
directions of the incoming light received from the one or more
light sources such that outgoing light emanating from the lens
elements is collimated in a first direction but diverges along a
different, second direction.
The lens elements can be configured to receive the incoming light
from the one or more light sources through the diffractive elements
of the lens element and the outgoing light emanates out of the lens
elements from the biconic refractive elements of the lens elements.
Optionally, each of the lens elements is configured to form a
different diverging beam of the outgoing light. Each of the lens
elements can be configured to form the diverging beam of the
outgoing light such that the diverging beam emanating from each of
the lens elements only partially overlaps the diverging beam
emanating from at least one neighboring lens element of the lens
elements. Each of the lens elements can be configured to form the
diverging beam of the outgoing light such that the diverging beam
emanating from each of the lens elements has a different central
angle than the diverging beam emanating from other lens elements in
the lens elements.
Optionally, the lens elements are configured to receive the
incoming light from laser diodes as the light sources. Each of the
lens elements can be configured to receive a portion of the
incoming light from a different light source of the one or more
light sources.
In one example, the lens elements are static, nonmoving bodies that
change the directions of the incoming light received from the
plural light sources. The lens elements do not move while
diffracting and/or refracting the light such that the outgoing
light emanating from the lens elements is collimated in the first
direction but diverges along the second direction. The lens
elements are disposed side-by-side along the second direction in
one embodiment.
In one embodiment, a method (e.g., for providing a lens array
assembly) includes obtaining a grayscale photomask, applying a
photoresist to a first side of an optic body, forming one or more
insoluble portions in the photoresist by exposing the photoresist
to a developing light through the grayscale photomask, and exposing
the one or more insoluble portions in the photoresist and one or
more portions of the optic body on the first side that are outside
of the one or more insoluble portions of the photoresist to an
etchant. The etchant forms biconic refractive surfaces in plural
lens elements on the first side of the optic body. The lens
elements are configured to change directions of incoming light
received from one or more light sources such that outgoing light
emanating from the lens elements is collimated in a first direction
but diverges along a different, second direction.
Optionally, the etchant forms the biconic refractive surfaces in
the lens elements on the first side of the optic body such that
different lens elements have different biconic refractive surfaces.
Obtaining the grayscale photomask can include exposing high energy
beam selective glass to one or more electron beams. In one
embodiment, the etchant is a plasma etchant.
The lens elements that are formed by the etchant can be microlens
elements having largest outside dimensions of no more than 3.4
millimeters in a first direction and no more than 2.2 millimeters
in a different, second direction.
Exposing the one or more portions of the optic body to the etchant
does not remove any more than 62.5 micrometers from the optic body
in one embodiment. Exposing the one or more portions of the optic
body to the etchant optionally removes no more than 32 micrometers
from the optic body.
The method optionally can include obtaining a different grayscale
photomask, applying additional photoresist to an opposite, second
side of the optic body, forming one or more insoluble portions in
the additional photoresist by exposing the photoresist to the
developing light, and exposing the one or more insoluble portions
in the photoresist and one or more portions of the optic body on
the second side that are outside of the one or more insoluble
portions of the photoresist to the etchant. The etchant forms
diffractive surfaces in the lens elements on the second side of the
optic body. Optionally, exposing the one or more portions of the
optic body on the second side to the etchant removes no more than
3.2 micrometers from the optic body. Another embodiment for
manufacturing the lens arrays is to use direct write printing of
precursor lens materials on a substrate to form the desired
diffractive shapes. The precursors can be sol-gel solutions or can
contain nanoparticles that are subsequently thermally processed for
form solid microlens parts. Yet another embodiment uses the method
of nano-imprint lithography to form the micro lenses. In yet
another embodiment, microcontact printing is used as a method of
manufacturing the microlenses.
In one embodiment, a lens array assembly includes plural lens
elements each configured to receive incoming light from one or more
light sources. The lens elements include biconic refractive
elements on first sides of the lens elements and including
diffractive elements on opposite, second sides of the lens
elements. The lens elements are configured to form different
diverging beams of the outgoing light such that the diverging beams
emanating from the lens elements have different central angles. The
lens elements can be configured to form the diverging beams of the
outgoing light such that the diverging beam emanating from each of
the lens elements only partially overlaps the diverging beam
emanating from at least one neighboring lens element of the lens
elements.
As used herein, an element or step recited in the singular and
proceeded with the word "a" or "an" should be understood as not
excluding plural of said elements or steps, unless such exclusion
is explicitly stated. Furthermore, references to "one embodiment"
of the presently described subject matter are not intended to be
interpreted as excluding the existence of additional embodiments
that also incorporate the recited features. Moreover, unless
explicitly stated to the contrary, embodiments "comprising" or
"having" an element or a plurality of elements having a particular
property may include additional such elements not having that
property.
It is to be understood that the above description is intended to be
illustrative, and not restrictive. For example, the above-described
embodiments (and/or aspects thereof) may be used in combination
with each other. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
subject matter set forth herein without departing from its scope.
While the dimensions and types of materials described herein are
intended to define the parameters of the disclosed subject matter,
they are by no means limiting and are exemplary embodiments. Many
other embodiments will be apparent to those of skill in the art
upon reviewing the above description. The scope of the subject
matter described herein should, therefore, be determined with
reference to the appended claims, along with the full scope of
equivalents to which such claims are entitled. In the appended
claims, the terms "including" and "in which" are used as the
plain-English equivalents of the respective terms "comprising" and
"wherein." Moreover, in the following claims, the terms "first,"
"second," and "third," etc. are used merely as labels, and are not
intended to impose numerical requirements on their objects.
Further, the limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn. 112(f), unless and until such claim
limitations expressly use the phrase "means for" followed by a
statement of function void of further structure.
This written description uses examples to disclose several
embodiments of the subject matter set forth herein, including the
best mode, and also to enable a person of ordinary skill in the art
to practice the embodiments of disclosed subject matter, including
making and using the devices or systems and performing the methods.
The patentable scope of the subject matter described herein is
defined by the claims, and may include other examples that occur to
those of ordinary skill in the art. Such other examples are
intended to be within the scope of the claims if they have
structural elements that do not differ from the literal language of
the claims, or if they include equivalent structural elements with
insubstantial differences from the literal languages of the
claims.
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